1. Technical Field
The present invention relates in general to disk drives and, in particular, to an improved system, method, and apparatus for a lightweight spoiler wing design for depopulated disk drives.
2. Description of the Related Art
Generally, a data access and storage system consists of one or more storage devices that store data on magnetic or optical storage media. For example, a magnetic storage device is known as a direct access storage device (DASD) or a hard disk drive (HDD) and includes one or more disks and a disk controller to manage local operations concerning the disks. The hard disks themselves are usually made of aluminum alloy or a mixture of glass and ceramic, and are covered with a magnetic coating. Typically, one to six disks are stacked on a common spindle that is turned by a disk drive motor at several thousand revolutions per minute (rpm).
A typical HDD also utilizes an actuator assembly. The actuator moves magnetic read/write heads to the desired location on the rotating disk so as to write information to or read data from that location. Within most HDDs, the magnetic read/write head is mounted on a slider. A slider generally serves to mechanically support the head and any electrical connections between the head and the rest of the disk drive system. The surface of the slider facing the disk is aerodynamically shaped to create an air bearing in order to maintain a uniform distance from the surface of the rotating disk, thereby preventing the head from undesirably contacting the disk.
Typically, a slider is formed with an aerodynamic pattern of protrusions on its air bearing surface (ABS) that enables the slider to fly at a substantially constant height close to the disk during operation of the disk drive. A slider is associated with each side of each disk and flies just over the disk's surface. Each slider is mounted on a suspension to form a head gimbal assembly (HGA). The HGA is then attached to a semi-rigid actuator arm that supports the entire head flying unit. Several semi-rigid arms may be combined to form a single movable unit having either a linear bearing or a rotary pivotal bearing system.
The head and arm assembly is linearly or pivotally moved utilizing a magnet/coil structure that is often called a voice coil motor (VCM). The stator of a VCM is mounted to a base plate or casting on which the spindle is also mounted. The base casting with its spindle, actuator VCM, and internal filtration system is then enclosed with a cover and seal assembly to ensure that no contaminants can enter and adversely affect the reliability of the slider flying over the disk. When current is fed to the motor, the VCM develops a torque that is substantially proportional to the applied current. The arm acceleration is therefore substantially proportional to the magnitude of the current. As the read/write head approaches a desired track, a reverse polarity signal is applied to the actuator, causing the signal to act as a brake, and ideally causing the read/write head to stop and settle directly over the desired track.
In the prior art, a number of solutions have been proposed to enhance the air flow within hard disk drives, such as bypass channels located adjacent to the disk pack. For example, some disk drives have air guides that only guide a central portion of the flow of air back to the disks. Other disk drives have housings with doors that guide the flow of air from the disks to a filter, or they use diverter ramps that also only affect a central portion of the air flow.
Some disk drives utilize a spoiler wing that is inserted between the media storage disks. See, e.g., FIG. 1, wherein airflow 11 between a plurality of disks 13 is diverted by conventional spoilers 15 having a solid, rectangular cross-sectional profile in a fully populated disk drive 17. In fully populated drives (i.e., those that contain the maximum number of disks possible), the spoiler thickness is usually maximized to its nominal clearance, but is limited to the allowable stack dimensional tolerance. In drives designed for computer servers, this nominal clearance is typically around 0.4 mm.
Depopulated disk drives contain a number of media storage disks that is less than the maximum number of disks allowable. In order to maintain maximum coverage (i.e., blocking of airflow to actuator arms, and/or increasing of flow into a bypass channel), the nominal clearance between spoiler and disk in depopulated disk drives is also kept to a minimum. For example, as illustrated in FIG. 2, the depopulated drive 21 lacks at least one disk between the two disks 23 that are shown. This configuration naturally increases the size and weight of the spoiler wing 25. However, the mass increase due to the simple increase in spoiler wing thickness serves no aerodynamic purpose with regard to airflow 27. On the other hand, with respect to structural integrity, having a large wing 25 between the disks 23 can have an adverse effect on performance, such as droop, worsened shock response, etc. Thus, an improved design that overcomes the disadvantages of the prior art would be desirable.